These are usually anti-spyware or security software applications that use various forms of deception and/or unethical means or show a history of negligent false positives to goad the end user to make a purchase.

In some cases these applications maybe downloaded with some form of unwanted software at which point the rogue application is offered to the customer as a way to remove the unwanted software.

Comment:

WinAntivirus may collect the user's information.

From the Privacy Policy:
They may disclose collected user information to advertisers and/or business partners.
Known to issue questionable false positives on clean installs of Windows XP.

Screenshots:

Win Antivirus 2007

Win Antivirus 2007 more

WinAntiVirus says they will keep the user information confidencial but the Privacy Policy says they disclose the user information to business partners.